A study on design optimization of conical bolt in the TF coil structure of the KSTAR Tokamak

摘要

The goals of the KSTAR project are to develop a steady-state-capable advanced superconducting Tokamak and establish a scientific and technological basis for a Korean nuclear fusion power station. The KSTAR Tokamak comprises a magnet system, vacuum vessel, and cryostat, thereby facilitating vacuum conditions for plasma gas at high temperatures, along with low-temperature helium gas for cooling. The TF coil structure, a part of the magnet system, is constructed and jointed with 16 pieces at 22.5-degree intervals using a conical bolt and shear key. The main function of the conical bolt in the inner and outer inter-coil structures is to resist the in-plane and out-of-plane forces and increase the toroidal and intercoil shear stiffness. Therefore, the conical bolt must be dimensionally optimized to reduce the stresses at each connecting part. Accordingly, shape optimization of the conical bolt was carried out using SZGA, and the stresses were analyzed by ANSYS.